1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display for realizing an increased viewing angle by dividing the arrangement direction of liquid crystal material in a pixel area, and a fabricating method thereof.
2. Discussion of the Related Art
Liquid crystal display (LCD) devices have many advantageous characteristics including low voltage drive, low power consumption, short response time, small size, light weight, small thickness, full color image display and others characteristics. Thus, application of the LCD devices in various types of consumer electronics, from a watch, a calculator, a PC monitor, a notebook, a PDA, an aeronautical monitor, a TV, a mobile phone and other electronics is increasing. Generally, the liquid crystal display devices are classified into a twisted nematic TN type liquid crystal display device, an IPS type liquid crystal display device, and a vertical alignment VA type liquid crystal display device in accordance with the arrangement shape of liquid crystal materials.
The liquid crystal materials used in the TN type liquid crystal display device has a twisted shape arranged in spiral orientation. The spiral orientation further includes that the liquid crystal material is disposed in parallel and having the regular interval with each other. The major axis of the liquid crystal material is arranged to change continuously. And visual characteristic is determined in accordance with the arrangement of the major axis and minor axis of the liquid crystal material. However, the TN type liquid crystal display device has a poor comparison ratio because light is not completely shut off at an off state. In addition, the comparison ratio changes with angles, and the brightness of middle scale reverses with change in the comparison ratio, thus, it is difficult to obtain a stable picture. Furthermore, the poor comparison ratio causes a viewing-angle problem such that the picture quality is not symmetric to the front surface.
On the other hand, the VA liquid crystal display device has the liquid crystal materials arranged vertically to the substrate surface in a voltage-absent state. The liquid crystal materials are aligned in several directions when the voltage is applied to show various characteristics such as improved comparison ratio and faster response speed. In addition, when the direction of the alignment of the liquid crystal materials is divided into designated several directions and a compensation film is used, the increased viewing angle might be realized effectively.
Recently, in the VA liquid crystal display device, a method of forming a rib defined as a triangle protrusion on the substrate inducing an electric field is suggested. In this method, the liquid crystal material has a negative dielectric anisotropy surrounded by a vertical alignment film along the induced electric field, or an aperture pattern is formed in a transparent electrode. Accordingly, the alignment of the liquid crystal material is controlled. At this moment, a shape of a 4 division alignment pattern used in the rib or the aperture pattern indicates the maximum efficiency in light utilization.
The VA liquid crystal display device, where the alignment of the liquid crystal materials is controlled by the rib of the related art method, forms a thin film transistor and a pixel electrode on a lower substrate. The rib is formed of an organic photosensitive insulating material on the pixel electrode. In addition, when the voltage is applied between the pixel electrode and a common electrode formed on an upper substrate, an electric field distortion is generated by the rib. And, arrangement of the liquid crystal material is changed having the rib at its center. As a result, a multi-domain is formed within the liquid crystal cell, and therefore, the viewing angle is increased.
However, the liquid crystal display of the related art requires the rib formed by a separate mask process and complicates the production process of the liquid crystal display device.